Geographic Range

The range of Bothrops asper includes the northwestern coast of South America from Ecuador to Venezuela, Trinidad, and north as far as Mexico. More specifically, in Mexico and Central America Bothrops asper is found north to the Southern Tamaulipas and south to the Southeastern Yucatan Peninsula. It dwells in the lowland Atlantic coastal areas of Nicaragua, Costa Rica, and Panama. Terciopelos (Bothrops asper) are also found in the northern areas of both Guatamala and Honduras. (Campbell and Lamar, 2004; O'Shea, 2005; Sasa, et al., 2009)

In South America these vipers are typically found west and north of the Andes, though there are exceptions, most notably in Venezuela where it can be found in the San Cristobal and Barquiseto Depressions in the Southeast region of the country. Bothrops asper is found on the Pacfic coastal plains and Andes Pacific versant from Columbia to as far south as the border of Peru and Ecuador. These snakes are also found in Northern Peru near the Pacific coast. In Columbia their range extends from the Pacific to the Carribean coastal plain as well as deeper within the country in the valleys of the Andes. Bothrops asper lives in sympatry with Bothrops atrox in central northern Columbia and certain areas of Venezuela. Bothrops atrox typically ranges further south in the Amazonian countries, but due to its similar appearance and overlapping distribution of Bothrops asper the snakes are often mistaken for one another. To further confusion, Bothrops asper was once considered a subspecies of B. atrox. (Campbell and Lamar, 2004; Sasa, et al., 2009)

Habitat

Bothrops asper is primarily found in the tropical rainforest, the tropical evergreen forest, and the outer edge of savannas, but has also been found in a wide variety of other habitats including lowland and lower mountainous regions, dry regions of some tropical deciduous forests, and the cloud forests of Mexico. Bothrops asper prefers higher levels of humidity but adults may be found in desert areas as they are at less risk for dehydration than their juvenile counterparts. In Ecuador, Terciopelos inhabit the low montane wet and dry forests as well as the coastal cloud forests. Bothrops asper is known to move in to newly cleared agricultural land areas in many countries as well as the forested uplands in Trinidad. These vipers are mainly terrestrial, but some juveniles are known to climb trees. They have been documented at elevations from sea level to 2,640 m above sea level. (Campbell and Lamar, 2004; Cisneros-Heredia and Touzet, 2004; O'Shea, 2005)

Physical Description

Members of the genus Bothrops are distinguished by their broad, flattened heads which are set apart from the rest of the body. Their eye lids (canthus) are very distinct. In drier regions, terciopelos have more scales to prevent water loss. Bothrops asper varies greatly phenotypically across its geographic range. This has led to the confusion between it and other species, most notably Bothrops atrox, which is similar in color but often contains yellow or rust like tones and rectangular or trapezoidal blotches. The head of Bothrops asper is medium to dark brown or even black. It may have occipital botches or streaks that range from indistinct to distinct, but usually are absent. The underside is most often pale yellow. Individuals may weigh up to 6 kg and typically measure 1.2 to 1.8 m in length. (Campbell and Lamar, 2004; O'Shea, 2005; Saldarriaga-Córdoba, et al., 2009; United States Navy, 1962)

Like most other Bothrops, B. asper has different patterns and colors on its dorsal and ventral sides and also exhibits a postorbital stripe. The ventral side is yellow, cream, or a whitish gray, with dark blotches (mottling) that increases in frequency towards the posterior end. Ventrolaterally, the viper has alternating dark gray scales which are paler towards the medial line. Dorsally, the viper is olive, gray, brown, grayish brown, tan or at times nearly black. It has dark triangles with pale edges laterally, which range in number from 18 to 25. Apices either alternate or are reflective of each other over the middorsal line. In the interspaces, there are dark, paravertebral blotches. An individual may have a yellow zig-zag shaped line on each side of the body. (Campbell and Lamar, 2004)

Terciopelos exhibit great sexual dimorphism. From birth, males are notably smaller in size than females. Females have thick, heavy bodies and can reach up to 10 times the size of males. Males have 161 to 216 ventral scales and 57 to 81 subcaudals. Females have 187 to 240 ventrals and 46 to 70 subcaudals. Juvenile females have a brown tail tip while males have a yellow tail tip. Prior to sexual maturation, males completely lose their yellow tip. (Campbell and Lamar, 2004; Sasa, et al., 2009)

Development

Reproduction

Unlike many vipers, there are no documented cases of male-male combat in Bothrops asper. Often females will mate with more than one male in a mating season. Mating includes a series of movements of the male who then slowly chases an accepting female. He often bobs his head at her side. The female then stops movement and extends her posture to mate. It is not known whether this species exhibits annual or biennial reproduction. (Sasa, et al., 2009; Solórzano and Cerdas, 1989)

Bothrops asper is considered the most prolific snake in all of the Americas. It breeds seasonally, usually during the rainy season when food is readily available. Males are known to follow females during the mating season in some regions. Fertilization is internal. Because terciopelos have a large geographic range, the time and length of reproduction varies greatly. For instance, in the Atlantic population of Costa Rica, B. asper mates in March, but in the Pacific region, it mates from September to November. This variation continues throughout Central and South America. There is a positive correlation between the body size of the female parent and the number of offspring she produces. After a gestation period of 6 to 8 months, females give birth to 5 to 86 viviparous young. These young terciopelos weigh between 6.1 and 20.2 grams each. There is also some evidence of long term sperm storage by the females to delay fertilization. Females are 110 to 120 cm at sexual maturity, while males average at 99.5 cm. (Campbell and Lamar, 2004; Sasa, et al., 2009; Solórzano and Cerdas, 1989)

Breeding season for Bothrops asper varies. Some populations are known to mate in March, and give birth in September-November. Others mate from September to November and parturition occurs from April to June.

Range number of offspring

5 to 86

Range gestation period

6 to 8 months

Females build up fat stores which lead to a release in hormones that stimulate ovulation. Females gestate for 6 to 8 months before giving birth to live young. There is no parental care.

Parental Investment

pre-fertilization

provisioning

protecting

female

pre-hatching/birth

provisioning

female

protecting

female

Lifespan/Longevity

Recapture of the species is uncommon, so longevity in the wild is unknown. However, it is estimated that lifespan in the wild is similar to that in captivity, which ranges from 15 to 21 years based on zoo-keeping records. (Bowler, 1977; Sasa, et al., 2009)

Range lifespanStatus: captivity

15 to 21 years

Behavior

Like much of Bothrops, B. asper is a nocturnal, solitary species. Activity varies seasonally, with B. asper becoming less active in colder and dryer months. Terciopelos are most often found near river and stream banks, basking in the sun during the day and under forest cover ready to ambush during the night. The viper also exhibits an S-coiled defense display when threatened by another species. Juveniles are known to climb trees and also to exhibit caudal luring, a use of their different colored tail tips to lure prey. (Campbell and Lamar, 2004; Sasa, et al., 2009)

Home Range

Because B. asper is highly sedentary, ambushing to capture prey, the viper usually does not stray more than 1200 m over a two-night period and maintains a much smaller activity center than its home range. Terciopelos only leave this activity center in the absence of food or sufficient humidity. They have an estimated territory range of 37,100 m. (Sasa, et al., 2009)

Communication and Perception

Communication and perception is not well studied in Bothrops asper. However, the species is named for its loreal heat-sensing pit which it uses at night to detect prey. Males follow females to show they are interested in mating, and will exhibit head-bobbing motions if the female allows him to approach.

Food Habits

Bothrops asper, due to its vast distribution, feeds on a wide variety of prey. The size, strength, and extremely toxic venom make terciopelos effective predators. In adult years, they have been known to feed on mammals, amphibians, and reptiles, but are not limited to these groups. Juveniles feed on small lizards and even large insects such as Scolopendra angulata.

Predation

Though well camouflaged, large, and venomous Bothrops asper has many predators, notably mussuranas (Clelia clelia). Mussuranas are snakes known to use their own venom and constrictive abilities to prey on other snakes. The blood of Clelia clelia contains an inhibitor of some the powerful toxins of the venom of terciopelos. Raptors, such as laughing falcons (Herpetotheres cacchinans), swallow-tailed kites (Elanoides forficatus), and crane hawks (Geranospiza caerulescens) are also important predators of terciopelos. The most effective are laughing falcons which can successfully defeat incredibly large female terciopelos. (Campbell and Lamar, 2004)

Ecosystem Roles

Bothrops asper has many parasites. Internal parasites include the nematodes Filaria, Rhabdias vellardi, Kalicephalus inermes, trematodes (Ochetosoma genus), and flatworms (Acanthocephala). Parasitic protozoans include hemogregarianes as well as amoeba and amoeba-like organisms. These have been known to cause gastroenteritis and hepatitis, among other illnesses. External parasites include several ticks, including Amblyoma savanae and Amblyoma dissimile, a known vector of hemogregarianes. (Sasa, et al., 2009)

Economic Importance for Humans: Negative

Bothrops asper is responsible for the most deaths by venomous snakes in most of its geographic range. Often living close to humans in lowland areas and having highly-toxic venom results in a significant impact in the areas it inhabits. Its well studied venom is hemorrhagic, myonecrotic and proteolytic. It can cause incredible pain, necrosis of the region, and progressive edema. (Campbell and Lamar, 2004)

Conservation Status

Urbanization, deforestation, contamination, and agriculture have resulted in the declining number of Bothrops asper in Ecuador. In spite of this, some are able to live and even thrive in open and suburban zones. It has been suggested that the Ecuadorian B. asper be placed as a species of "Least Concern" on the IUCN Redlist, though the species is currently not evaluated. (Cisneros-Heredia and Touzet, 2004)

In Costa Rica, human impact has seemed to favor Bothrops asper. Terciopelos have been able to prosper in certain agricultural fields such as banana, cacao and coffee. Even though they are adaptable, some areas have seen a decline which is thought to stem from more drastic environmental changes and decline of prey. (Sasa, et al., 2009)

Contributors

Glossary

living in the southern part of the New World. In other words, Central and South America.

agricultural

living in landscapes dominated by human agriculture.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

coastal

the nearshore aquatic habitats near a coast, or shoreline.

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

delayed fertilization

a substantial delay (longer than the minimum time required for sperm to travel to the egg) takes place between copulation and fertilization, used to describe female sperm storage.

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

drug

a substance used for the diagnosis, cure, mitigation, treatment, or prevention of disease

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

infrared/heat

(as keyword in perception channel section) This animal has a special ability to detect heat from other organisms in its environment.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

polyandrous

Referring to a mating system in which a female mates with several males during one breeding season (compare polygynous).

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

sperm-storing

mature spermatozoa are stored by females following copulation. Male sperm storage also occurs, as sperm are retained in the male epididymes (in mammals) for a period that can, in some cases, extend over several weeks or more, but here we use the term to refer only to sperm storage by females.

tactile

uses touch to communicate

terrestrial

Living on the ground.

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

venomous

an animal which has an organ capable of injecting a poisonous substance into a wound (for example, scorpions, jellyfish, and rattlesnakes).

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

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The Animal Diversity Web is an educational resource written largely by and for college students. ADW doesn't cover all species in the world, nor does it include all the latest scientific information about organisms we describe. Though we edit our accounts for accuracy, we cannot guarantee all information in those accounts. While ADW staff and contributors provide references to books and websites that we believe are reputable, we cannot necessarily endorse the contents of references beyond our control.

This material is based upon work supported by the
National Science Foundation
Grants DRL 0089283, DRL 0628151, DUE 0633095, DRL 0918590, and DUE 1122742. Additional support has come from the Marisla Foundation, UM College of Literature, Science, and the Arts, Museum of Zoology, and Information and Technology Services.